Fuel cell technologies present opportunities for the commercial development of long-lasting power sources for portable power and electronics applications. With the trend toward greater portability of a wide array of consumer electronics, some fuel cell technologies offer promising alternative power sources to meet the increased demand for portable power. Fuel cells can potentially replace or favorably compete with the various types of high density batteries presently used in consumer electronics, such as nickel metal-hydride and lithium ion battery systems, as well as relatively inexpensive alkaline batteries. These types of batteries are less than satisfactory power sources for such consumer electronics as laptop computers and cellular phones either due to their low power density, short cycle life, rechargability or cost. In addition, all these types of batteries present environmental safety concerns and costs for proper disposal.
Fuel cell systems are electricity-generating devices that convert chemical energy into useable electrical energy via electrochemical reactions involving a fuel reactant, such as natural gas, methanol, ethanol, or hydrogen, and an oxidizing agent, typically oxygen from ambient air. Fuel cell systems may be divided into “reformer-based” systems, i.e., those in which the fuel is processed in some fashion before it is introduced into the cell, or “direct oxidation” systems, i.e., those in which the fuel is fed directly into the cell without internal processing. Most currently available stationary fuel cells are reformer-based fuel cells. However, fuel processing requirements for such cells limits the applicability of those cells to relatively large systems. As such, direct oxidation fuel cells, which do not have the need to reform fuel, are attractive power sources for handheld portable electronics.
Although direct oxidation fuel cell systems are a promising power source, they are limited by the fact that they are designed to operate using a designated fuel or a limited number of appropriate fuels. Prior fuel cell systems have not been designed to ensure that only a compatible fuel is delivered to the fuel cell system.
Additionally, prior fuel cell systems have been limited because they have not been designed to regulate the delivery of fuel in a manner that is consistent with the fuel cell system's ability to receive fuel. As a result, the performance of these prior fuel cell systems has not been optimized.
Further, prior fuel cell systems have not been designed to ensure that only devices capable of safely delivering fuel to the fuel cell system are used. As a result, prior fuel cell systems have posed risks to operators when improper refilling devices have been used.
Prior fuel cell systems have also had problems with the management of the operation of the fuel cell system. For example, prior fuel systems have not been able to monitor the level or amount of fuel remaining to be able to signal an operator when a new fuel canister is needed or to automatically replenish fuel as it is depleted. Additionally, prior fuel cell systems have not been able to monitor characteristics of the fuel and to adjust the fuel supply characteristics based on the monitored data.